Anil Dash has posted that as of today Movable Type is now open source. As most other bloggers I have chosen WordPress for my platform since it is easily customizable and has excellent documentation. Also, creating plugin-ins in PHP is a snap with WordPress. I have yet to thoroughly analyze Movable Type though and may consider making the move if there is a big upside to switching platforms.
There are already a number of large sites that are leveraging the Movable Type platform including the soon to go public, Huffington Post. I have done installations of both WordPress and Movable Type for clients and I have to say that Movable Type was always the easier install. Prior to caching plugins provided by WordPress, I would have recommended Movable Type as a platform for high traffic sites. That’s no longer the case and I always default to WordPress.
Can you think of any reason to switch to Movable Type aside from their willingness to embrace open standards?